This makes the links embedded in the UI invalid

• Detect when GitHub is in dark mode
• Render in dark mode

(Currently, the injected content uses a light theme)

Extension no longer activates at all, it seems

Example: https://github.com/a/a

Related: #1

• Show files with similar names in the folder
• Show history of files with that name

These should only be shown when the errored segment is possibly a folder/file in a repo. This may require more knowledge about GitHub URL structure.

GitHub redesigned their 404 page and the selector this extension uses to detect the 404 page no longer exists!

Recovery steps:

1. Retry a few times, with exponential backoff
2. Show "Retry" button with failure state (eg "GitHub isn't working")